Abstract: Based on the metamaterial concept,a broad bandwidth high-gain and low radar cross section(RCS)patch antenna was designed and fabricated on the thinner substrate with the lower permittivity.The periodically loaded complementary triangular electromagnetic resonator(CTER)on the upper patch and strip-line gaps on the bottom ground plane were etched,respectively.Simulated analysis demonstrates that,due to the left-handed characteristics of metamaterial,the effective medium parameters of substrate of antenna are affected,the wave propagation direction of antenna is further altered which induces the strongest radiation in horizontal direction instead of the vertical direction of the conventional patch antenna. Compared with the original antenna,the novel antenna has a wider bandwidth significantly broadened from about 2.9% to about 64.5%,and also a low voltage standing wave ratio;the antenna has the lower RCS reduced above 5dB within the whole operation bandwidth at boresight direction,and the most reduction 22dB is obtained.Experimental data show good agreement between the simulation and measured results.